How can I compare versions of an OCAD map ?

Question

Planners in our clubs are very slack when it comes to updating our online copy of club maps. I often end up in a situation where I need to compare map versions so that I can pick the correct (or at least best) one as the canonical one.

Is there any mechanism for comparing OCAD files ?

Answer 1

There seem to be two ways of doing this.

1. There is an open source Windows utility OcadDiff (available from here) written by Yannis Güdel which shows you the differences between the two files graphically. This is probably the easiest way to do it.
2. You can use OCAD itself to create a map of all of the elements in Map A but not Map B. Then reverse the process to show those in Map B but not Map A. Pauli Ojanperä has documented how to do this here. This will require OCAD 11 or later, the Select commands are not available in OCAD 10 or earlier.

In case Pauli's instructions disappear, here's just the text from his explanatory page:

Let's say we have map versions A and B. They are almost identical with only some differing elements, for example some incremental modifications in the vegetation or so. No symbols or colors have been modified. This is how to proceed to reveal those differences:

1. Load the map A. (File - Open)
2. Select all objects in the map. (Select - Select All)
3. Save the selection. Accept the name "Selection 1" (Select - Save Selection)
4. Import the map B. Place with offset 0,0 and do not import any symbols or colors. (File - Import...)
5. Select duplicate objects. (Object - Topology - Select Duplicate Objects)
6. Delete the objects. (Object - Delete)
7. Reload the saved "Selection 1" i.e. all objects in the original map A. (Select - Reload Selection - Selection 1)
8. Delete the objects. (Object - Delete)

Now, in front of you, you have only those objects that are in the map B but are not in the map A. Before saving the result under a new filename (File - Save As), you might do some tidying: remove all background maps, delete unused symbols and colors, and optimize the map to not unnecessarily save all those deleted objects that will always remain hidden in OCAD's object storage until you optimize them away.